Method and apparatus for pressing of textile fabric continuously

ABSTRACT

AN IMPROVED METHOD AND APPARATUS FOR CARRYING OUT THE CONTINUOUS PRESSING OF TEXTILE FABRICS WITHOUT CREATING &#34;PRESSING BELT MARKS&#34; UPON THE FABRICS. DURING THE PRESSING OPERATION, THE INTERMEDIATE PORTIONS OF THE PARTICULAR LENGTH OF FABRIC BEING PRESSED IS PRESSED UNDER A UNIFORM HIGH TEMPERATURE WHILE THE END PORTIONS OF THE LENGTH OF FABRIC ARE SUBJECTED TO A DECREASING TEMPERATURE GRADIENT PROGRESSIVELY DECREASING FROM THE TEMPERATURE OF THE INTERMEDIATE PORTION TO A MUCH LOWER TEMPERATURE. THE END PORTIONS OF EACH LENGTH OF FABRIC ARE THEN SIMILARLY REHEATED DURING THE NEXT PRESSING CYCLE AND THE CUMULATIVE HEATING AND PRESSING OF THE END PORTIONS SUBSTANTIALLY EQUALS THAT APPLIED T THE INTERMEDIATE PORTION SO THAT NO &#34;BELT MARKS&#34; ARE CREATED. SEVERAL DIFFERENT MEANS FOR HEATING THE PRESSING PLATES OF THE INVENTION ARE ILLUSTRATED.

Och 1971 KAZUTOMO ISHIZAWA FI'AL 3,509,391

METHOD AND APPARATUS FOR PRESSING 0F TEXTILE FABRIC CONTINUOUSLY Filed Dec. 19, 1969 5 Sheets-Sheet 1 METHOD AND APPARATUS FOR PRESSING OF TEXTILE FABRIC CONTINUOUSLY Filed Dec. 19, 1969 Oct 1971 KAZUTOMO ISHIZAWA FI'AL OEm/E TEMPERATURE 1 METUI M w E H O D I 8 G Tmw W 0 4E 0 m W wmmomwmww THE m3 M53528; w QEmE Lo mmwzvai w m IOE 2P w w m S S w W DI 00b 1971 KAZUTOMO ISHIZAWA 3,509,391

METHOD AND APPARATUS FOR PRESSING OF TEXTILE FABRIC CONTINUOUSLY Filed Dec. 19, 1969 5 Sheets-Shoot 5 FGHIJK mwmm 0o mmp mmm 56% @Z mmmmm MEASURED POSITIONS Och 1971 KAZUTOMO ISHIZAWA ETA!- 9 METHOD AND APPARATUS FOR PRESSING OF TEXTILE FABRIC CONTINUOUSLY Filed Dec. 19, 1969 5 Sheets-Sheet 4 P30 Q R d fiy gfifl W Fig. 75

U al/ /H 9 R E P 150 5 Pb I Rb U) I im .1 Z o L X L) E THICKNESS OF FABRIC- Oct 1 A KAZUTOMO ISHIZAWA ETAL 3,609,891

METHOD AND APPARATUS FOR PRESSING OF TEXTILE FABRIC CONTINUOUSLY Filed Dec. 19, 1969 5 Sheets-Sheet 5 6 szwm United States Patent Im. c1. D06f 71/00, 73/00 US. Cl. 3817 Claims ABSTRACT OF THE DISCLOSURE An improved method and apparatus for carrying out the continuous pressing of textile fabrics without creating pressing belt marks upon the fabrics. During the pressing operation, the intermediate portions of the particular length of fabric being pressed is pressed under a uniform high temperature while the end portions of the length of fabric are subjected to a decreasing temperature gradient progressively decreasing from the temperature of the intermediate portion to a much lower temperature. The end portions of each length of fabric are then similarly reheated during the next pressing cycle and the cumulative heating and pressing of the end portions substantially equals that applied to the intermediate portion so that no belt marks are created. Several dilferent means for heating the pressing plates of the invention are illustrated.

The present invention relates to an improved method and apparatus for the continuous flat pressing of textile fabric, and more particularly relates to a method and apparatus for preventing the formation of so-called pressing belt marks.

Generally, in a finishing process for textile fabrics such as worsted or woolen fabrics, certain union fabrics made of worsted or woolen yarn or blended yarn containing some synthetic fibers, pressing of the fabrics is employed for glazing, providing dimensional stability and improving the hand feeling quality of the fabric. It is well-known that a paper pressing method has been applied for the above-mentioned purpose.

The paper pressing operation performed on high quality worsted fabric is inevitable for attaining very elegant luster and good hand feeling. However, a long period of time is required to complete the above-mentioned paper pressing operation, and moreover, the folds of the fabric are free from the paper pressing operation. Therefore, in the paper pressing operation, it is required to transfer the fabric which has completed a first operation at the other lift table and at the same time it is necessary to change the insertion of the press-papers. For carrying out the abovementioned paper pressing operation, in the conventional paper pressing equipment, a plurality of presses and lifts are required for use.

To eliminate the above-mentioned drawbacks involved in the paper pressing method, a well-known continuous flat press machine, such as the Hattersely Pickard-Flat Press, was developed and these machines are now commercially employed for the continuous pressing operation.

In the aforementioned continuous flat press, there is a well-known drawback known as a pressing belt mark which occurs at duplicate pressed portions of the fabric and consequently the application of the continuous flat press is limited to certain types of fabrics under limited conditions. In other words, it is impossible to apply the conventional continuous flat press to each and every kind of fabric.

The principal object of the present invention is to Patented Oct. 5, 1971 ice provide an improved method and apparatus for carrying out the continuous flat pressing of fabrics without any occurrences of a pressing belt mark.

Further features and advantages of the invention will be apparent from the ensuing description when taken with reference to the accompanying drawings to which the scope of the invention is in no way limited.

FIG. 1 is a side view of a main portion of the conventional continuous flat press, partly in section, according to the present invention,

FIG. 2 is an explanatory diagram illustrating the functional operation of the continuous flat press shown in FIG. 1,

'FIGS. 3A and 3B are a pair of explanatory diagrams illustrating the variation of the working temperature of the flat press shown in FIG. 2,

FIGS. 4A and 4B are diagrams showing the relationship between the thickness of the processed fabric and the operating temperature obtained by actual mill tests utilizing the conventional flat press,

FIG. 5A is a cross section of a heating press plate useable for practicing the present invention, taken along line 5A5A in FIG. 5B.

FIG. 5B is a press plate,

FIG. 6 is an explanatory drawing illustrating the relationship between the pressing temperature and the positions of the heating press plate and the relationship between the positions of the heating plate and assumed thickness of the fabric pressed by the above-mentioned portion of the heating plate according to the present invention,

FIGS. 7A, 7B and 7C are drawings illustrating the structure of the heating press plate and the working effect thereof, and

FIGS. 8A, 8B, 8C and 8D are cross-sectional views of modified heating plates, according to the present invention.

For a better understanding of the present invention, the principle of operation of the continuous fiat press in hereinafter illustrated.

As shown in FIG. 1, the conventional fiat press has been designed consisting of a fixed top pressing plate In, intermediate superposed pressing plates 2a and 2b, and a moveable pressing plate 1b, all of which are heated. A ram (not shown) is disposed below the moveable pressing plate 1]) and is selectively actuated to displace the pressing plate 1b in an upward direction. Therefore, two units for carrying out the pressing operation are formed, one by the top pressing plate 1a coating with the intermediate pressing plate 2a, and the other by the pressing plate 1b coacting with the intermediate pressing plate 2b. Since the functions of these two units are iidentical, the pressing operation of the flat press is hereinafter illustrated only for the first unit.

A fabric 3a is passed between the top pressing plate 1a and the intermediate pressing plate 2a in such a way that the fabric 3a passed to and fro about five times by guide rollers so that five thicknesses may be simultaneously pressed at one time.

The pressing plates (1a, 1b, 2a and 2b are provided with a plurality of heating conduits 6 passing therein. whereby the pressing plates 1a, 1b, 2a and 2b are heated by a heating medium passing through the heating conduit 6. When the rollers and fabric are at rest, pressure is applied by the moveable ram and after a giventime, the pressure is released and the pressing plate 2a falls apart in accordance with the downward motion of the moveable plate together with the ram. Then the rollers are driven so that the fabric is advanced forward by a predetermined distance afterwhich the rotation of the rollers is stopped and the pressing operation is carried out by the above mentioned action. The operation cycle may be repeated,

for example, five times in a period of passing the fabric 3a through the pressing unit.

Referring now to FIG. 2, the fabric 3a which is fed into the space existing between the heated pressing plate 1a and the intermediate pressing plate 2a, is subjected to a first pressing operation, The working length of the heated pressing plate 1a is represented to be I and the length of the pressed portion of the fabric 3a taken along the length thereof is also represented by l. The abovementioned length of the pressed portion of the fabric 3a is hereinafter referred to as the press-length of the fabric. After completion of the first pressing operation, the fabric 3a is moved forward by a distance m. In this moving motion of the fabric, it is required that the following relation lgm be satisfied. On the contrary, if I is smaller than in, a portion of the fabric represented by a length (ml) is not subjected to the pressing operation. -In the above-mentioned general condition represented by (15m), a point P on the fabric 3a, which is positioned at rear ends. of the pressing plates 1a and 2a, is displaced to be represented by a point Q after the abovementioned forward displacement of m distance, as shown in FIG. 2. Supposing a point of the fabric 13a facing the forward ends of the pressing plates 10 and 2a is represented by R, the distance QB equals (l-m), therefore, l=m=+[5, where {3 represents the distance 6B. In the above-menioned general condition of (12m), a point P on the fabric 3a, which is positioned at the rear ends of the pressing plates 1a and 2a, is displaced to be represented by a point Q after the above-mentioned forward displacement of m distance, as shown in FIG. 2. Supposing a point of the fabric 3a facing the forward end of the pressing plates 1a and 2a is R, represented by Q R is subjected to the duplicate pressing operation so that a wellknown belt mark is generated into the fabric 3a.

With respect to the causes of generating the abovementioned belt mark, further detailed analysis is hereinafter made. It should be understood that the pressure and humidity contained in the fabric, the temperature and the duration time for carrying out the pressing operation are main factors for considering the cause of generating luster on the fabric. In the above-mentioned factors, the temperature for carrying out the pressing operation is particularly important to attain the uniform result of the pressing operation.

Referring to FIGS. 3A and 3B, during the pressing operation by utilizing the continuous flat press shown in FIG. 1, the fabric 31: is subjected to the operation at least five times. And the operating temperature imparted to the fabric 3a is the highest at the contacting position with the pressing plates 1a, 1b, 2a and 2b, and the farther away the fabric 30 is from the pressing plates 1a and 2a or 1b and 2b, the lower is the operating temperature imparted to the fabric 3a between press-papers.

Therefore, the operating temperature imparted to the fabric 3a at the A and E positions is the highest and that imparted to the fabric 3a at the D and B positions is medium and that imparted to the fabric 3a at the C position is the lowest.

In FIGS. 4A and 4B, two examples illustrating the relation between the pressing temperature and the thickness of the pressed fabric are shown. The diagram of FIG. 4A represents the test results of a pure wool fabric Matweave (thickness of the fabric is 0.620 mm.), while diagram of FIG. 4B represents the test results of blended mohair-tropical (wool 50%, polyester fiber 50%, thickness of the fabric is 0.370 mm.). The thickness of the fabric is measured after completion of the pressing operation carried out under a pressure of 20 kg./mm. at several temperatures from 20 to 110 C. for sec.

As clearly shown in FIGS. 4A and 4B, the higher the pressing temperature, the more the pressing operation is effectively carried out. As clearly shown in FIGS. 4A and 4B, the pressing effect is poor where the pressing temperature is below 60 C. Therefore, a belt portion of the .4 fabric 3a, which corresponds to the belt portion mi in FIG. 2, is subjected to a duplicate pressing operation with the highest pressing temperature so that this portion of the fabric becomes thinner than the other portions, therefore, a belt-like thin portion is produced. This belt-like thin portion of the fabric 3n has already been referred to as a pressing belt mark. Since the pressing efiect in the positions represented by B, C and D in FIG. 3A is insufficiently weaik, it is impossible to completely eliminate the pressing belt mank on the fabric 3a. Further, a pressing belt mark made by the final pressing position E (in FIG. 3A) is so distinctive that it is also impossible to eliminate. In case of utilizating the above-mentioned continuous flat press, it is necessary to apply high temperatures in order to obtain the distinct effect of the pressing operation, however, the pressing operation of the fabric at a high temperature results in the occurrence of the distinct belt marks imparted to the fabrics. On the contrary, if the pressing operation is carried out at 10W temperature so as to prevent the occurrence of the pressing belt mark, an insufficient pressing operation is only carried out.

From a careful study of the above-mentioned analysis, an improvement of the continuous flat press has been found. This improvement is based upon the following principle, that is, the operating temperature imparted to the duplicate-pressing portion (TR of the fabric 3A (in FIG. 2) should be set at lower than the normal operating temperature so that the pressing effect imparted to the portion Q R of the fabric 3a by the duplicate pressing operations is almost the same as that imparted to the other portions of the fabric 3a by a single pressing operation whereby the distinct pressing belt mark can be eliminated.

In FIGS. 5A and SE, a typical press plate of the continuous flat press according to the present invention is shown. The elongated pressing plate 5 is provided with a sinuous conduit or a plurality of conduits 6 passing therethrough for flowing therein a heating medium, such as steam or hot water etc., so that the pressing plate 5 is uniformly heated. Further, the leading end or feed side end portion and the trailing end or delivery side end portion of the pressing plate 5 are provided with cooling conduits 7a and 7b for cooling the respective portions of the pressing plate 5. Cool water flows into the conduits 7a and 7 b. The outer side of the cooling conduits 7a and 7b are provided with recesses 8a and 8b for cooling the above-mentioned end portions as shown in the drawing. Therefore, when the heating medium having a predetermined temperature is fed into the conduit 6 while cool water is fed into the conduits 7a and 7b, a major longi- -tudinal center portion of the pressing plate 5 is uniformly heated whereas in both end-portions of the pressing plate 5, the temperature of the pressing plate 5 is lowered as shown in FIG. 6.

In FIG. 6, the variation of the temperature of the pressing plate 5 is shown by a curve I, wherein F, G, H, I, I and K on the abscissa represent the measured positions on the pressing plate 5 as shown in FIG. 5A, and the ordinate represents the measured temperature of the pressing plate 5 as measured during an actual pressing operation. In the above-mentioned measurement, the temperature of the major center portion of the pressing plate 5 is C., and the temperature of the cooling water is 242 C., the flow rate of the cooling water in the conduits 7a and 7b is 30 l./ min and room temperature is 28 C. The temperature of the pressing plate 5 is lowered from point F to point K and a decreasing temperature gradient is established in the pressing plate surface progressively decreas* ing from the major center portion to each end thereof as represented by curve I. Therefore, by applying the test results shown in FIGS. 4A and 4B, the variation of the relative thickness of the fabric pressed by the abovementioned portions F, G, H, I, J and K can be estimated as shown by a curve II, in FIG. 6. In this curve II, the ordinate represents the decrease fabrics thickness.

As shown in FIGS. 7A, 7B and 7C, when the fabric 3a is introduced between the pressing plates into a pressing zone and fiat pressed by applying the pressing plate 5 according to the present invention, the variation in the thickness of the pressed fabric is represented by a solid line curve I in FIG. 7B. The solid curve I is composed of a pair of curved portions Pa-Pb and Rb-Ra symmetrically positioned at both end thereof and representing the thickness of the trailing and leading ends, respectively, of the fabric web and an intermediate horizontal portion Pb-Rb representing the thickness of the major center portion of the fabric web.

In the curved portion PaPb, the thickness of the fabric 3a gradually decreases to the thickness represented by the horizontal portion Pb-Rb and in the curved portion Rb- Ra, the thickness of the fabric 3a gradually increased from the level of the horizontal portion Pb-Rb to the same level as the point Pa.

As already illustrated, the above-mentioned variation of the fabrics thickness depends upon the pressing temperature of the surface of the pressing plate 5. Consequently, the length of fabric corresponding to the curved portion PaPb, coincides with that of the portion of the fabric corresponding to the curved portion Rb-Ra. Therefore, the length of the fabric portions corresponding to Pa-Pb, Pb-Rb, Rb-Ra are hereinafter respectively represented by a, m and whereby the pressing length I can be represented by the expression:

Next, after displacement of the fabric 3a so that the point P on the trailing end of the fabric 3a is displaced to the point Q, the fabric 3a is then subjected to another pressing operation.

A dot-line curve II in FIG. 7B represents the variation in the thickness of the fabric 3a resting on the press plate. After completion of the succeeding pressing operation, the variation of the thickness of the fabric is represented by .the curve shown in FIG. 7C. As can be clearly understood, the variation in the thickness of fabric in a range Q R is leveled by the succeeding pressin goperation.

The relation between the pressing length l and the dis placement distance m of the fabric and the distance between the Q and R positions should be satisfied by the following equation mgm where m =l2a.

and the temperature in this lower temperature zone should be decreased to the outside edge X, Y of the pressing plate. On the contrary, if l2a m, a pressing belt mark having a width represented by (l2am) is made. In spite of applying the formula oc= /2 (lm to the pressing plate shown in FIG. 7A, it is preferable, in a practical sense, to set the variation of the temperature of the pressing plate, operating condition and displacement distance m of the fabrics so that a is slightly larger than /2(lm). In FIGS. 8A, 8B, 8C and 8D, modified embodiments of the pressing plate according to the invention are shown, that is the pressing plate 5 is provided with a pair of cooling conduits 7 or With at least one radiator 8 (FIG. 8B), with at least one deep lateral groove 9 which disturbs the heat conduction (FIG. 8C) or with at least one deep lateral groove 10 filled with an adiabatic substance, such as asbestos, glass fibers or silicon, which disturbs the heat conduction FIG. 8D, at both end portions thereof.

What is claimed is:

1. In a method for carrying out a continuous fiat pressing operation by pressing a portion of a fabric having a predetermined length (1) under heat and then moving the pressed and heated portion of fabric a predetermined distance (m), an improvement comprising pressing said portion offabric while heating same with a heating surface defining a pair of side heating zones having a temperature gradient sloping down to each end of said side heating zones and an intermediate main heating zone maintained at a uniform temperature arranged between said side heating zones in accordance with the condition wherein a represents the length of each of said side heating zones.

2. In a continuous flat press comprising a plurality of heating flat pressing plates, each of said flat pressing plates consisting of a pair of side heating portions and an intermediate main heating portion arranged between said side heating portions, each of said side heating portions being provided with means for creating a heating surface having a temperature gradient sloping down to an end of said side heating portion, and wherein said intermediate main heating portion is provided with means for creating a uniform temperature heating surface.

3. In a continuous fiat press according to claim 2, wherein said means for creating said uniform temperature heating surface upon said intermediate main' heating portion of each of said flat pressing plates comprises conduit means for flowing a heating medium.

4. In a continuous fiat press according to claim 2, wherein said means for creating said heating surface having said temperature gradient comprises at least one cooling conduit disposed in each of said side heating portions of each of said flat pressing plates.

5. In a continuous flat press according to claim 2, wherein said means for creating said heating surface having said temperature gradient comprises at least one cooling conduit disposed in each of said side heating portions and means defining a recess formed at an outer edge portion of each of said side heating portions of each of said flat pressing plates.

6. In a continuous flat press according to claim 2, wherein said means for creating said heating surface having said temperature gradient comprises means defining at least one hollow space for radiation formed in each of said side heating portions of each of said fiat pressing plates.

7. In a continuous flat press according to claim 2, wherein said means for creating said heating surface having said temperature gradient comprises means defining at least one deep lateral groove formed at an opposite side of said heating surface of each of said side heating portions of each of said fiat pressing plates.

8. In a continuous flat press according to claim. 2, wherein said means for creating said heating surface having said temperature gradient comprises means defining at least one deep lateral groove formed at an opposite side of said heating surface of each of said side heating portions of each of said flat pressing plates, and an adiabatic substance disposed within said groove.

9. A method of fiat pressing a fabric web to a uniform thickness comprising: providing a fabric web to be uniformly flat pressed to a preselected thickness; advancing a predetermined length of said fabric web having leading and trailing ends into a pressing zone; applying pressure to both sides of said predetermined length of fabric web while differentially heating said predetermined length of fabric web in said pressing zone to effect fiat pressing of same to a preselected thickness along subtsantially the entire length thereof and formation of progressively thicker end portions thicker than said preselected thickness at said leading and trailing ends thereof; then advancing the fabric web until the next successive length thereof equal to said predetermined length and including as a leading end thereof said trailing end of the preceding predetermined length of fabric lies within said pressing zone; then repeating said applying and heating step to effect flat pressing of said next successive length of fabric web to said preselected thickness along substantially the entire length thereof including said leading end and formation of a progressively thicker portion thicker than said preselected thickness at the trailing end thereof; and repeating both said last-mentioned advancing and said applying and heating steps until said fabric Web is flat pressed to a uniform thickness throughout its entire length.

10. A method according to claim 9; wherein each said applying and pressing step comprises fiat pressing said predetermined length of fabric Web between two heated surfaces each of which is heated to a lesser temperature at its end portions than at its remaining center portion.

11. An apparatus for flat pressing a length of fabric comprising: a pair of oppositely spaced-apart elongated pressing plates each having an elongated flat pressing surface; heating means for heating said pressing plates to effectively maintain a major longitudinal center portion of said elongated flat pressing surf-aces at a constant temperature level; means for establishing a decreasing temperature gradient in each longitudinal end portion of each said elongated flat pressing surface progressively decreasing from said major center portion to one longitudinal end portion thereof; and means mounting said elongated pressing plates for movement towards and away from one another to effect flat pressing of a=fabric web disposed therebetween.

12. An apparatus according to claim 11; wherein said means for establishing said decreasing temperature gradient comprises cooling means disposed within said elongated pressing plates for cooling each longtiudinal end portion of each said elongated fiat pressing surface relative to said constant temperature level.

13. An apparatus according to claim 11; wherein said means for wtablishing said decreasing temperature gradient comprises means defining a hollowed out portion in each longitudinal end portion of each said elongated flat pressing surface of sufiicient dimension to establish therein said decreasing temperature gradient.

14. An apparatus according to claim 11; wherein said means for establishing said decreasing temperature gradient comprises means defining at least one groove within each said longitudinal end portion of said elongated flat pressing surface effective to establish therein said decreasing temperature gradient.

15. An apparatus according to claim 14; further including an adiabatic material disposed within each said groove.

References Cited JORDAN FRANKLIN, Primary Examiner G. V. LARKIN, Assistant Examiner U .5. Cl. X.R. 2195 34 

